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Broadband dielectric spectroscopy and aging of glass formers

We present the results of aging experiments on a variety of glass formers, including xylitol, glycerol, propylene carbonate, and [Ca(NO3)2]0.4[KNO3]0.6 (CKN). In addition, broadband dielectric spectra of xylitol and CKN are provided. We demonstrate that, irrespective of which dielectric quantities (dielectric constant, loss and modulus) are analyzed, and irrespective of the spectral region where they have been measured, the aging-time dependence always is governed by the structural rearrangements constituting the alpha-relaxation. If the time dependence of the structural relaxation time during aging is taken into account, relaxation times and stretching parameters, fully consistent with equilibrium data, are obtained. In CKN, both the structural relaxation time and the strongly decoupled conductivity relaxation time are deduced from the same dielectric aging experiment.